Preheat oven to 450 degrees F.
Coat the chicken with olive oil and season well with salt and pepper.
Grill the chicken until just cooked through, 4-5 minutes a side for boneless chicken breasts.
Cool and then slice into thin strips or shred.
In a small skillet, heat 3 tablespoons oil over medium high heat until very hot.
Dip the edge of a tortilla into the oil to check, it should sizzle immediately.
Using tongs, put a tortilla into the pan and cook until soft and lightly brown on each side, about 15-20 seconds per side (at the most).
Then drain on paper towels.
Add oil as needed and continue until all 12 tortillas are done (I skipped this part since i made my own tortilla at the same time).
Instead of stacking the tortillas, I rolled them so it'll fit in my baking dish.
Pour half of the green chili sauce in a 9x13 baking dish.
Reserve half for topping.
I made 8 tortillas, so i divided the grilled chicken and half of the cheeses into 8 portions.
Lay tortilla wrap on a work surface, put chicken and grated cheese.
Roll and put on the baking dish with sauce seam side down.
Repeat with the remaining tortillas.
When done, pour the other half of the sauce over the top with the remaining cheese.
Bake until the cheese becomes bubbly. SERVE HOT!